I think I have managed to find an interesting trouble in the stable version of FMOD Ex (4.06.15, but it still exists in 4.06.16) & FMOD Designer (1.07.12). When I switch car-type (equipped with rpm and load parameters, mixed from different car sounds) event’s distance parameter based attenuation to "Custom" (effects used: Volume and Low-Pass Filter, and they are pushed to zero in ab. 500 units) and then I try listen to the cars in game, FMOD produces random sound glitches and popping noises for these events in certain distances (mostly when they exceed or near to exceed their so-defined maximal distance). However, when I do not try to push the volume and low-pass filtering stricly to zero (only to half of it), it sounds correctly.